Apparatus for stringing a line underneath a cross member

Abstract

A stringing apparatus for stringing a sock-line, optionally a phase line, within a closed framed opening of a power line tower of H-frame, portal or corset type uses a helicopter for pulling the sock-line where the stringing apparatus is suspended from the helicopter by a tow-line and the sock-line is fastened to it. The stringing apparatus comprises an arcuate channel which is attached to the sock-line and a rotating open spoke star-wheel defining legs the ends of which travel inside the channel and allows a continuous revolution of the star wheel thus allowing the closed frame cross member to travel through one of the gaps between the legs while the sock-line passes to the underside of the cross member and the tow line passes over the cross member.

The invention claimed is: 
     
       1. Apparatus for attachment to a tow line of a helicopter for stringing a sock-line underneath a cross member of a power line tower comprising:
 a first member for engaging the tow line such that the first member is suspended by the tow line from the helicopter for forward movement over the cross-member; 
 a second member for attachment to the sock-line for pulling the sock-line to a position adjacent the cross-member; 
 and a rotary member connected between the first member and the second member for the second member to be towed forwardly by the forward movement of the first member; 
 the rotary member including at least one opening for receiving the cross-member therein; 
 the rotary member being rotatable to allow said at least one opening to move rearwardly relative to said forward movement of the first and second members so that the second member moves underneath the cross-member as the first member movers over the cross-member; 
 the rotary member being arranged to maintain connection between the first and second members as said at least one opening moves rearwardly. 
 
     
     
       2. The apparatus according to  claim 1  wherein the rotary member includes a plurality of legs defining between each leg and a next leg said at least one opening. 
     
     
       3. The apparatus according to  claim 2  wherein the legs maintain connection between the first member and the second member as the rotary member rotates. 
     
     
       4. The apparatus according to  claim 2  wherein the rotary member rotates around a single axis and ends of the legs engage and move along an arcuate member. 
     
     
       5. The apparatus according to  claim 4  wherein the arcuate member defines a guide track and the ends of the legs include guide elements for moving along the guide track. 
     
     
       6. The apparatus according to  claim 5  wherein the guide elements comprise rollers. 
     
     
       7. The apparatus according to  claim 4  wherein the rotary member comprises a star wheel where the legs are defined by outwardly projecting elements of the star wheel. 
     
     
       8. The apparatus according to  claim 2  wherein the rotary member is carried by a link which allows the rotary member to rotate relative to the link. 
     
     
       9. The apparatus according to  claim 8  wherein the link is a clevis within which the rotary member rotates. 
     
     
       10. The apparatus according to  claim 1  wherein the rotary member is carried by the first member. 
     
     
       11. The apparatus according to  claim 3  wherein, as the rotary member rotates, at all times at least two of the legs maintain connection between the first member and the second member and define said at least one opening therebetween. 
     
     
       12. The apparatus according to  claim 1  wherein the rotary member is unpowered and is driven in rotation by contact with the cross-member. 
     
     
       13. A method for stringing a sock-line underneath a cross member of a power line tower comprising:
 attaching a tow line to a helicopter; 
 attaching a first member to the tow line such that the first member is suspended by the tow line from the helicopter for forward movement over the cross-member; 
 attaching a second member to the sock-line for pulling the sock-line to a position adjacent the cross-member; 
 connecting the first member to the second member for the second member to be towed forwardly by the forward movement of the first member; 
 connecting the first member to the second member by a rotary member including at least one opening for receiving the cross member therein; 
 as the first member passes over the cross member and the second member moves underneath the cross-member in said forward movement, causing the rotary member to rotate to allow said at least one opening to move rearwardly relative to said forward movement of the first and second members so that the cross member passes between the first and second members; 
 the rotary member being arranged to maintain connection between the first and second members as said at least one opening moves rearwardly. 
 
     
     
       14. The method according to  claim 13  wherein the rotary member includes a plurality of legs defining between each leg and a next leg said at least one opening. 
     
     
       15. The method according to  claim 14  wherein the legs maintain connection between the first member and the second member as the rotary member rotates. 
     
     
       16. The method according to  claim 14  wherein the rotary member rotates around a single axis and ends of the legs engage and move along an arcuate member. 
     
     
       17. The method according to  claim 16  wherein the arcuate member defines a guide track and the ends of the legs include guide elements for moving along the guide track. 
     
     
       18. The method according to  claim 14  wherein, as the rotary member rotates, at all times at least two of the legs maintain connection between the first member and the second member and define said at least one opening therebetween. 
     
     
       19. The method according to  claim 13  wherein rotary member is carried by the first member.